. A practical treatise on the use of the microscope, including the different methods of preparing and examining animal, vegetable, and mineral structures. Microscopes; Microscopy. PRACTICAL TREATISE ON The microscope used by. Hooke was a compound one with three lenses, and is ihown at fig. 1, and also n the sixth figure of the lirst plate of his work, in vhich figure it wiU be perceived that he likewise â epresents a method of iUu- ninating opaque objects, practised even at the pre- sent day, the plan being to place a globe of glass filled with salt water or brine immediately in front of the l
. A practical treatise on the use of the microscope, including the different methods of preparing and examining animal, vegetable, and mineral structures. Microscopes; Microscopy. PRACTICAL TREATISE ON The microscope used by. Hooke was a compound one with three lenses, and is ihown at fig. 1, and also n the sixth figure of the lirst plate of his work, in vhich figure it wiU be perceived that he likewise â epresents a method of iUu- ninating opaque objects, practised even at the pre- sent day, the plan being to place a globe of glass filled with salt water or brine immediately in front of the lamp, the pencil of rays from the globe is received by a small planoconvex lens, placed with its convex side nearest the globe, by which the pencil is condensed upon the object. Hooke also informs us of an accurate method of finding the magnifying power of a com- pound microscope, than which a better plan has not been suggested in modern times, and as it would be difficult to make his description shorter or more intelligible than it is, his own words will here be transcribed:â" Having rectified the microscope to see the desired object through it very distinctly, at the same time that I look upon the object through the glass with one eye, I look upon other objects at the same distance with my other bare eye; by which means I am able, by the help of a ruler divided into inches and small parts, and laid on the pedestal of the microscope, to cast, as it were, the mag- nified appearance of the object upon the ruler, and thereby exactly to measure the diameter it appears of through the glass, which being compared with the diameter it appears of to the naked eye, will easily afford the quantity of its mag- ; To Hooke also belongs the merit of having first made globule lenses of high power, an invention which Hart- soeker has also claimed; but if the dates of the works of these respective authors be consulted, it will be seen that the Micrographia of Hooke was publis
Size: 1497px × 1668px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, booksubjectmicroscopes, booksubjectmicroscopy
